Data from this lab has demonstrated that sensory experience can produce changes in the expression of transcriptional regulatory factors (such as NGFI-A) and their potential target genes (such as glutamic acid decarboxylase (67 kD form) and synaptophysin) in the barrel cortex. This system serves as a model to study how sensory experience can effect plasticity in neuronal cells, particularly since many of the identified target genes for NGFI-A have a functional role at the synapse. In contrast to a physiological stimulus, this lab has shown that seizures inhibit the transcriptional activation of these synaptic target genes. Based on these preliminary studies, this proposal seeks to test the hypothesis that seizures will interfere with the physiological transcriptional activation that occurs in the cortex after sensory experience, and therefore may interfere with the plasticity that occurs after sensory experience. Predictions based on this hypothesis will be tested by studying animals exposed to both physiological and seizure stimuli. Gene expression will be monitored by a combination of mRNA (RT-PCR and in situ hybridization) and protein (Western blot and immunohistochemical) techniques. The interactions of the transcription factors with their target genes will be addressed using gel shift analysis and transient co-transfection assays. Long term measures of synaptic plasticity will be studied at both the light microscopic and electron microscopic level. The results of these studies extend our current understanding of both the changes in transcriptional activity that occur after physiological neuronal stimulation, as well as the effects of seizure activity on these pathways.